This invention relates to a drive motor in particular for a fan wheel of a radiator of a motor vehicle.
Such drive motor includes a stator and a rotor rotating about an axis of rotation relative to the stator. The drive motor can be formed as electric motor, but for example also as internal combustion engine, in which a rotor rotates relative to a stator, and for example serves for driving a fan wheel of a radiator with which an internal combustion engine of a motor vehicle is cooled.
In operation of a drive motor it is required to cool individual components of the drive motor, in order to prevent overheating of the components. In an electric drive motor formed as d.c. machine, this applies for example to a commutator which for commutation includes brushes which slidingly rest against the rotor and are heated as a result of the rotary movement of the rotor in operation of the drive motor. Current-carrying windings for generating a magnetic field and an electronic control unit of the drive motor likewise must be cooled in operation, in order to ensure a reliable operation of the drive motor.
In a drive motor known from DE 103 48 214 A1 a stator carrying windings includes cooling tubes through which a coolant flows for cooling the windings. The use of such cooling tubes for cooling windings only is possible when the windings are firmly arranged on a stator.
For cooling a commutator in particular including brushes, a drive motor known from DE 101 19 450 A1 in the form of a commuted d.c. machine uses an air flow which is generated by a fan connected with the d.c. machine and is guided through the d.c. machine in axial direction. For guiding the air flow channels are provided in a stator, which guide the air flow through the d.c. machine.
In an electric motor known from U.S. Pat. No. 5,095,236 a fan wheel is provided on a drive shaft in addition to a rotor carrying windings for cooling the motor. Fan wheel and rotor are formed separately.